-LRB- CNN -RRB- -- Among the 35,000 runners lining up at this Sunday 's London Marathon , there 'll be the usual pre-race nerves , waves of excitement , and focus on the task ahead .

This year , there will also be silence .

Six days after Boston 's Marathon was rocked by the bombing which killed three people and injured more than 180 , the world will be turning its gaze to London 's premier race .

It will be unlike any other race in its 32-year history , as thousands of competitors and spectators observe a 30-second silence ahead of the starting gun , in remembrance of Boston 's casualties .

Haunting images of bloodied victims scrambling down smoldering streets , past upturned stands which just moments earlier had been filled with cheering family and friends , will no doubt loom large in the minds of Londoners this weekend .

Expect to see an ocean of black solidarity ribbons pinned to the chests of runners , as they wind their way past the Capital 's most iconic landmarks such as Big Ben and Tower Bridge .

In another act of solidarity , for every competitor who crosses the finishing line , race organizers plan to donate $ 3 to The One Fund Boston , set up to raise money for victims of the blasts .

Photos : After the explosion -- moment by moment

` In it together '

`` Now there is a huge feeling of defiance , '' three-time London winner Paula Radcliffe told CNN .

`` How dare someone attack sport and humanity in this way -- we are not going to be cowed , '' added the 39-year-old Radcliffe , who is the world marathon record holder .

Watch : Bombing victim could n't hear after blast

That defiance is shared by the thousands of competitors who run the London Marathon to raise money for myriad charities .

`` It 's important to see on mass that we 're in it together , '' said 36-year-old asset management worker , Ed Lucas , who will be running his first ever marathon on Sunday .

`` It does make you reassess the race . But I think if anything , it will make people a lot more determined -- Brits are quite stubborn , they do n't like being told what to do . ''

Another runner Matthew Huntington , 36 , said his family -- including his two and five-year children -- would be coming to watch him .

`` It never entered my mind to drop out and yes it made me even more determined to take part , '' added technical marketing manager Huntington . `` If you 're completely risk averse you would never leave the house . ''

Stepped-up security

Security will also be stepped-up at the event , which is the first international marathon to follow Boston .

There will be an increase in searches and officers on the street , London 's Metropolitan Police Commissioner , Bernard Hogan-Howard , said .

`` We 've no reason to think people are any less safe than they were before the terrible events in Boston , '' he added .

Olympic training

Last year 's Olympic Games has also bolstered London 's credentials when it comes to hosting safe , international sporting events , Britain 's culture secretary , Maria Miller , said .

`` You will know from London 2012 last year , this country has a great deal of experience of ensuring our sporting events go well and that security is at the heart of the planning process . The London Marathon is no different , '' she told the Commons this week .

Deputy Prime Minister Nick Clegg promised security would be `` double , triple , quadruple checked . ''

Show of support

With tight security measures in place , the public has been urged to get behind the great British sporting event -- as much for the competitors on the day as a sign of solidarity with Boston .

`` Obviously , in light of what happened in Boston , we 've had to have a look at security and we have a detailed and well-thought-out plan with the Metropolitan Police which we have year-in , year-out , '' London Marathon chief executive , Nigel Bitel , said .

`` It 's a great occasion , the London Marathon , and I know that people will want to come out and send a message of support to runners on the day . ''

Watch : Eyewitness images of blast

No fear

Similarly , reigning marathon champion , Wilson Kipsang , told competitors to try and put security issues out of their minds as they wind their way along the 42 kilometer route from Blackheath to Buckingham Palace , home of the Queen .

`` When you are running and you are thinking something like that can happen , you ca n't concentrate , '' the Kenyan told Athletics Weekly .

`` We should have no fear during the race because security matters will be put in place and we will run feeling free . ''

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Six days after Boston Marathon bombings , thousands of runners will compete in London

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Special event marked by 30 second silence , black solidarity ribbons

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Stepped-up security with increased searches and police on streets

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Olympics 2012 good training ground for staging international sporting events